Tracking and storing position and movement data has become integral in many activities. For example, navigation and mapping, surveying, fleet tracking, and robotics applications are just a few common applications where the ability to track position and motion has become important. Many of these applications suffer from inaccuracies inherent in the position tracking technology itself. Moreover, in applications where highly accurate position data is necessary, a lack of accuracy may result in poor data and associated maps, and in some cases serious and costly problems, such as infrastructure damage, fires, explosions, and even injury or death in some cases.
For example, locating and documenting buried utilities such as water pipes, electrical power conduits or cables, or gas lines with a high degree of precision has become essential to maintaining and improving infrastructure, as well as to ensure the safety of humans living or working nearby. Buried utility locators (also denoted here in as a “utility locator,” “line locator,” or simply “locator” for brevity) are devices that are commonly used to find these kinds of underground utilities. One popular type of locator uses magnetic field sensing to locate utilities based on magnetic fields emitted from the utility. The magnetic fields are generated from currents flowing in the utility itself or, in some cases, in by current flowing in other associated conductors such as tracer wires or, in some cases, directly from a magnetic field sonde device (also denoted herein as a “sonde” for brevity) that is inserted into a pipe or other cavity and generates a dipole magnetic field at its point of insertion.
Some utility locators use other additional sensors to enhance locating ability. For example, satellite navigation systems such as global positioning satellite (GPS) receivers have been used to approximate the location of utilities. Even with enhanced capabilities of additional sensors and/or apparatus the accuracy of locating a buried utility with existing locators may be lacking due to the inherent imprecision of such known systems, such as when GPS receivers have poor satellite coverage or are subject to interference.
Accordingly, there is a need in the art to address the above-described as well as other position determination, tracking, and mapping related problems.